In hip joint operations the femoral neck is usually retained and the femoral head is fraised off. This enables a surface of a replacement femoral head or a femoral implant to be cemented onto or into the fraised femoral head. If a femoral implant is selected that is too small (e.g., an inner diameter of the implant is too small) and cemented on the fraised head, there exists the danger that the fraiser apparatus that processes the inner contour of the implant is unintentionally fraised into the femoral neck so as to cause a fracture of the femoral neck. If a femoral implant is selected that is too large, then the femoral implant may not be sufficiently flush with the femoral head or on the femoral neck.
In conventional methods, the implant size is pre-operatively determined using x-rays and templates. This procedure can be time-consuming and can include a number of possible inaccuracies due to projection errors. Further, the determined size may be intra-operatively verified by means of measuring templates or metal templates, which increases the amount of time expended in implementing the procedure.